Lawrence bradshaw



- No Drawing.

Patented July 18, 1933 UNITED STATES PATENT o FFICE LAWRENCE BRADSHAW, OF BAINIBRIDGE, YORK, ASSIGNOR TO THE CASEIN MANUFACTURING COMIANY OF AMERICA, IN C., 01'' NEW YORK, N. Y., A CORPORA- TION OF DELAWARE ADHESIVE AND PROCESS OF MAKING SAME This invention relates to improving the quality of cheap adhesives or glues made from peanut meal, slaked lime and alkali metal saltswith or without additional cellulose substances such as Wood meal, hull meal or other filling materials such as ground leather scrap.

I have previously described a glue suitable for gluing up plywood and the like, prepared from peanut meal, slaked lime and sodium salts which latter have the property of reacting with lime to produce'insoluble salts of calcium and liberate caustic soda. This glue 4 to wood by the machines can conveniently be made up in a dry state at the factory and subsequently mixed with water when required for use. The peanut meal employed is usually the pulverized press-cake of commerce, commonly sold as afeeding stufl', containing about 43% protein, and 6 to 8% residual oil. For use in glues this meal is usually re-ground so that substantially all of it will pass through a 120 mesh screen, or even finer. One part of the glue base thus prepared can be mixed with about 2 to 2 parts of water to make an adhesive of good Working qualities for applying to plywoodor veneers, the usual practice being to stir the mixture for fifteen to twenty minutes in order to obtain a fluid product of suitable consistency for applying employed in the art for this purpose.

The object of the present invention is to more fully-utilize the insoluble organic ingredientsof the glue by causing them to plump or swell up so that a'greater portion of water can be used and the volume of the glue increased withoutundue thinning, the consistency, of the glue being maintained;

and the glue can be distributed over a larger surface in the subsequent spreading operation. It is based upon the discovery that the addition of caustic soda to the fluid glue after the process of solution ofthe proteins by the alkali salts-of the glue-base issubstantially I I complete, produces a rapid thickening of the. glue, which can then' be diluted with water to restore it to the desired consistency, resultin in a great increase in the bulk or volume 0 Application filed January 2, 1980.. Serial No. 418,164.

weight of the dry glue base. This thickening is much greater thanwould be produced by equlvalent amounts of soluble sodium saltsto the dissolved glue, and I believe that it arises from the swelling action of the free caustic soda on the cellulose and starchy constituents of the glue.

While the peanut meal itself contains a substantial amount of fibre, other cellulose materials such as wood flour, bran, oat hulls, ground corn cobs, ground sugar cane are sometimes added to such meals to act as fillers in the glues, the use of such fillers having proved advantageous in some cases, for instance in the gluing'together of soft woods.

Such fillers, however, might be a source of Weakness rather than of strength when they are insufliciently plumped, and I have found that a comparatively small amount of free caustic soda is a much more effective plumping agent than a larger amount of sodium salts in presence of lime. The sodium salts commonly employed in making up a glue base are the phosphate, carbonate, sulfite and fluoride; the corresponding salts of potassium may likewise be employed.

The following examples will serve to illustrate the method of carrying out the invention, which however is not restricted to these examples.

Ewample'1.84 parts of peanut meal, 12

' parts of hydrated lime and 4 partsof sodium fluoride are mixed together to form a dry gluebase. 100 parts of this glue base are then mixed with 350 parts of water at about Fland well stirred for 15 to 20 minutes. Then parts of caustic soda dissolved in 14 parts of water are added and the stirring continued fora short time, say 1 to 5 minutes.

This liquid glue willaccordingly' be seen to contain, with 100 parts of the dry glue base, 364 parts of water, together with 7 parts of NaOH. .The amount of water is a little over 3.4 times the total amount of all the other constitutents. The glue is then ready 'to be applied to veneers for the making of plywood. This glue spreads. Well on the usual machines employed in the art for applying uid glue. n this example it will be noted that after 3 the glue at this stage to be too thin for use in 1 glue powder with the water, preferably not gluing up plywood. Within a very short time after adding the caustic soda, however,

it will be observed that the glue has thickened to a suitable consistency for this purpose.

Example 2.84 parts of peanut meal, 10 parts of hydrated lime, 3 parts of sodium fluoride and 3 parts of tri-sodium phosphate are mixed together dry to form a dry glue base. Subsequently when it is desired to use the glue, the base is mixed with about 3.7 times its own weight of water and stirred for 15 minutes. This produces a thin, liquid glue. 5 parts of caustic soda in the form of a 40% solution are then added and the stirring continued for about 2 minutes, when it will be found that the glue has thickened greatly and acquired a good body or consistency suitable for spreading. This liquid contains, per 100 parts of dry glue base, 377 parts of water, together with 5 parts of NaOH. The water is almost 3.6 times the total amount of all the other constituents.

Ema-mpZe-3.76 parts of peanut meal, 10 parts of wood flour, 10 parts of hydrated lim e, 3 parts of sodium fluoride and 1 part of sodium carbonate are mixed together to form a dry glue base. Subsequently 1 part of this glue base is mixed with about 3.8 parts of water'and stirred for about 15 minutes, which produces a very thin-flowing liquid glue. 6 parts of dry caustic soda are sprinkled into the liquid and the stirring continued for 3 to 5 minutes, when the caustic soda passes into solution and the glue thickens to a good,.

workable consistency. This liquid glue contains, with 100 parts of the dry glue base and 6 parts of caustic soda, 380 parts of water.

The water is over 3.5 times the total amount of the other constituents.

I call attention to the fact. that the caustic soda is added after the initial mixing of the less than 10 ininutes after the mixing operation is begun, by which'time the protein content of the glue is believed to be substan-' tially all dissolved. The agitation of the glue base. with water according to current practice usually requires about 20 minutes.

and I may add the caustic soda preferably after about 15 minutes and continue stirring to the end of the period. The proportion of the caustic soda may vary more or less, say from 3% up to 8% of the weight of the dry glue-base.

I claim:

1. A process of preparing fluid peanut.

nut meats from which the bulk of the peanut oil has been removed, sodium salts of acids which form insoluble .compounds with lime, and lime, and thereafter, but before use of the glue, adding caustic soda, whereby a substantial thickening of the fluid glue is effected, the total amount of water added being at least 3.5 times the weight of the dry glue base.

3. A process of preparing fluid peanut glue which comprises mixing with not below 3.5 parts of water, 1 part of a peanut glue base, comprising a major partof peanut meal, slaked lime equal to a minor fraction of the peanut meal and a still smaller amount of alkali metal salts capable of reacting with the slaked lime in the presence of water, and thereafter adding caustic alkali to the very thin liquid glue to effect a thickening thereof.

4. A process of making liquid glue of sufficient body for use in making plywood from veneers, w ich comprises adding a glue base to water, the glue base containin peanut meal as'its ma'or constituent together with slaked lime, a aline sodium salts and sodium fluorid, and after some mixing, adding 

